The market for electronic devices is increasingly determined by the demand for greater functionality at minimal device size. In order to meet these demands, not only the semiconductor components must be increasingly integrated, but miniaturization measures must also be taken in the packaging so that the savings may also be implemented at the chip level in the form of a size reduction of entire components. This is true both for the packaging of pure IC chips and also for the packaging of MEMS chips and a combination of both, as is typically used in sensors. It proves to be advantageous in this context to stack two or more chips. The footprint of the resulting component may be limited to the dimensions of the largest chip. The contacting of the individual chips among one another and also the external contacting of such a chip stack are advantageously performed via so-called through contacts. It is conventional to implement the through contacts in the form of contact holes, which extend from the chip front side up to the chip rear side, are filled using an electrically conductive material, and are electrically insulated with respect to the carrier material of the chip. Uniform filling of the contact holes is more difficult the higher the aspect ratio of the contact holes, i.e., the greater the ratio of hole depth to hole width.
Thinned chips, so-called thin chips, are preferably used to minimize the component height. They are typically not processed individually, but rather simultaneously for a plurality of chips in the wafer composite. Depending on the chip size and wafer size, several thousand components, which must be separated at the end of the manufacturing process, may be situated on one semiconductor wafer.
A method for simplifying the separation of chips is described in German Published Application 103 50 036. This method is used in particular during the manufacturing of thinned chips, whose functionality is only to be implemented in a surface layer of the semiconductor substrate. The lateral chip boundaries of this thin chip are fixed here with the aid of etched trenches, which completely penetrate the surface layer of the substrate. In addition, cavities are produced below the surface layer using superficial micromechanical methods, so that the individual chips are only connected via support elements in the area of a cavity to the substrate layer below this cavity. To separate the chips, these support elements are mechanically disconnected, for example, in a picking process in the scope of the single-chip mounting.